Those were good tries, everyone. Counting seemed to be a very popular strategy. One thing, though -- I was confused with your answers. I could not tell where you started counting or how many numbers you counted. It was also hard to tell if you counted up or down.

Here's how I did it:

I knew there were 5 coins in my pocket to start with. They were all dimes so I had 50 cents. Then, they doubled. 5+5=10, so now there were 10 coins in my pocket. They were all still dimes, so that would make $1.00.

The note said the coins would double again by lunch time. Well, 10+10=20. That would put 20 dimes in my pocket. They would all be dimes. If I count by 10s 20 times, I'll get 200 cents or $2.00.

Wow! Did you see how much writing it took to tell you all that! Sometimes you have to tell more than one sentence to explain yourself. You'll get the hang of it!

I'm proud of you all for trying this kind of question. It was a tough one! Thank you for taking a chance.